ABSTRACT In response to PAR-17-470, PR-OUTLOOK: ?Puerto Rico (PR) Young Adults? Stress, Contextual, Behavioral & Cardiometabolic Risk? will investigate psychosocial and sociodemographic determinants of cardiovascular disease (CVD) risk factors and overall cardiovascular health (CVH) among young adults (18-29 y) in PR, a markedly vulnerable but understudied population. Previous studies of CVD risk in Puerto Rico and elsewhere have largely focused on middle-age and elder adults, and there is little data on CVD risks and overall CVH among the current young adult population -a generation that grew during the obesity epidemic. Incident CVD and stroke have not declined over time or have even increased in younger individuals as opposed to in older adults. Our preliminary findings and Behavioral Risk Factor Surveillance System data suggest that Puerto Ricans aged 18-34 years have a high burden of CVD risk factors. No studies have examined overall CVH (a metric to assess progress toward the American Heart Association 2020 goals of improving CVH by 20% and reducing CVD mortality by 20%) in Puerto Ricans of any age. Evidence links psychosocial and neighborhood stressors with CVD risk factors but these associations have not been assessed among young adults in PR. In young adulthood, stress increases (i.e. financial, school-to-work, social/family transitions), behavioral risks peak, and health care is undervalued/prevention postponed. PR contextual factors (i.e., island?s financial crisis, hurricane Mara aftermath, neighborhood socioeconomics, urban vs. rural residence) also may contribute to CVD risk but have not been studied in young adults in PR. Puerto Ricans? resilient factors, including family/social support, spirituality, and religiosity may attenuate risk as these factors are of known benefit to the general population, but their protective impact in young Puerto Ricans is unknown. Our study will fill knowledge gaps of prevalence of CVD behavioral and cardiometabolic risk factors and overall CVH among young adults in PR, and ascertain their psychosocial (individual and neighborhood-level) and sociodemographic determinants. We will establish an island-wide cohort of 3,000 young adults (18-29 y) using a multi-stage sampling of probabilistic plus community approaches; conduct comprehensive assessments (survey, anthropometric, physiological), and establish a biorepository (blood, hair, saliva, urine, stool) for future longitudinal studies of CVD risk, CVH, and mechanisms. PR-OUTLOOK will extend the reach of the NHLBI-funded PROSPECT study and leverage already developed research infrastructure, island wide collaborations, and relevant study protocols to maximize synergy/optimize resources between studies. Our study will fill important knowledge gaps regarding CVD risk among young adults in PR and identify priority targets for medical, public health and policy interventions for early CVD prevention. We also are well positioned to conduct comparative studies with older island Puerto Ricans (PROSPECT), mainland Puerto Ricans (HCHS/SOL), and US Black and White young adults (CARDIA), as many assessment tools are shared between studies, further adhering to guidelines of the PAR.